If you can install Windows 7 on your PC, you will be able to install Windows 8 as well. That's a key goal of Microsoft Corp. (MSFT), which is currently crafting the OS -- due for release late next fall.

Microsoft Windows President Steven Sinofsky reports in his Building Windows 8 blog, "Our goal with Windows 8 from the beginning was to ship with the same system requirements as Windows 7."

While Microsoft aims to officially "only" hold steady in terms of minimum required hardware (which includes memory and processor) with the new release, it's also making it clear that its informal goal is to provide a superior memory footprint in Windows 8 versus its current flagship OS.

Mr. Sinofsky shows off a pair of screen grabs taken from Windows 7 (SP1) and Windows 8 machines running at idle after multiple clean reboots. The Windows 8 machine currently has 3 less system processes (9+% less) and has 124 MB (~20 percent) more "Available Memory" on his 1 GB notebook -- the Windows 7 minimum memory requirement.

It is fun to think about what the "low end" hardware looked like in 2009 and how you can't even find things like 256MB memory modules anymore. We wanted to ensure that people running on Windows 7-era hardware would have the option to easily upgrade their existing machines to Windows 8 and take advantage of the functionality it has to offer. We also expect that many machines that predate the Windows 7 release will run Windows 8 based on the experiences we’ve had with older machines we intentionally keep in our performance test infrastructure.

The reduction in number of services comes from what Microsoft calls a "start on demand" model. The basic premise here is that the service triggers when a cue is received (e.g. plugging in a USB drive), but then exits the memory space when the cue vanishes (e.g. the drive is unplugged) and a sufficient amount of time elapses.

Microsoft has also turned off, by default, services pertaining to the desktop, for builds aimed at tablets or other mobile devices. Microsoft believes that users will spend the majority of their time in the new Metro UI, interacting with Metro-enabled apps. If they need to use the desktop, appropriate services will start, but until they do, these services won't be taking up RAM.

Windows 8 also creates a new form of memory allocation -- "low priority" memory. Programmers will be able to use this to designate non-essential allocations, safeguarding users from memory shortages.

Microsoft points out that while memory may play a second fiddle to processor and screen power usage on mobile devices, it still can have a significant impact on battery life. Writes Mr. Sinofsky:

Something that might not be obvious is that minimizing memory usage on low-power platforms can prolong battery life. Huh? In any PC, RAM is constantly consuming power. If an OS uses a lot of memory, it can force device manufacturers to include more physical RAM. The more RAM you have on board, the more power it uses, the less battery life you get. Having additional RAM on a tablet device can, in some instances, shave days off the amount of time the tablet can sit on your coffee table looking off but staying fresh and up to date.

The memory usage that the Windows team is pulling is particularly impressive, when you consider that the clean install of Windows 7 tested does not include a running copy of Microsoft's Windows Defender anti-malware application. The Windows 8 clean install -- which uses less memory -- does include this running app.

States the blog:

NOTE: For Windows 8, a clean install also contains the extended Windows Defender technology, which, for the first time incorporates complete antimalware functionality – also optimized for memory and resource use per Jason’s blog about protecting you from malware. (This functionality does not exist on a clean install of Windows 7 where we would recommend that you add security software).

This development is definitely bad news for antivirus manufacturers like McAfee and Symantec Corp. (SYMC). While their products have come a long way from their bloated forms of yore, it seems unlikely that they will be able to keep pace with Windows Defender in terms of footprint. While the most cautious consumers may still pick them up for the potential of added protection via quicker malware definitions updates, many consumers will likely opt to solely rely on Microsoft's free protection.

At least one major A/V firm may have seen the writing on the wall. Intel Corp. (INTC) subsidiary McAfee heavily promoted its new hardware-level permissions defense at IDF 2011, which will be incorporated on a hardware level. Given that Microsoft is increasingly offering protections that meet or beat veteran security software vendors' offerings, others will likely follow in suit, either looking deliver hardware-enabled protections or defenses in unique third party programs, such as browsers.

Returning to the topic of memory use, it should be interesting to see what kinds of low-end systems that enthusiasts are able to squeeze Windows 8 onto. Windows 7 was installed and run on some torturously dated hardware -- but by the looks of it Windows 8 may be destined for even greater feats.

Now how do we go about replicating that brain and installing it into the the idiots of the world. You know, the buddy who won't stay off of pron sites and wants you to fix his computer which somehow seems to slow down only a few days after you wipe it clean.

The problem is, if a simpleton asked which AV software you use, and you say none, they may feel that they don't need to run any. "But you said that you don't use any, so why did I get the virus." Well, see above paragraph for the answer.